PRODUCING DEVICE FOR GLASS PREFORM

摘要

PURPOSE:To uniformly deposit a soot by keeping evacuating speed to optimum one in spite of the drawing-up position of a preform and stabilizing the flow of the soot in a chamber in the case of growing the preform by depositing the soot from a burner on the bottom end of a target rod in the chamber by VAD method. CONSTITUTION:The soot preform 20 is formed by depositing the soot from the burners 22. 23 on the bottom end of the target rod 21 rotating in the camber 10. The target rod 21 is drawn up in accordance with the growth of the preform. The chamber 10 is forcibly evacuated by a evacuating pipe 11 mounted in the chamber 10. The actual evacuating speed at each part of the evacuating pipe 11 is measured by an anemometer 14. The evacuating speed at each part is kept to optimum by controlling each of evacuation adjusters 12 with a computer 15.